Fuel burner plug



Sept. 5, 1967 Filed Dec. 20, 1965 P; w. FLECK ETAL FUEL BURNER PLUG FIG! 2 Sheets-Sheet 1 INVENTORS Ray 0. Gangewere Francis W. Fleck ATTORNEY Sept. 5, 1967 F. w. FLECK ETAL FUEL BURNER PLUG 2 Sheets-Sheet 2 Filed Dec. 20, 1965 United States Patent 3,339,614 FUEL BURNER PLUG Francis W. Fleck, Gladstone, Mich., and Ray 0. Gangewere, Wadsworth, Ohio, assignors to The Babcock & Wilcox Company, New York, N.Y., a corporation of New Jersey Filed Dec. 20, 1965, Ser. No. 514,916 9 Claims. (Cl. 158--1.5)

ABSTRACT OF THE DISCLOSURE This invention relates generally to fuel burning apparatus arranged to fire through a port in a combustion chamber wall, and more particularly to a fuel burner wherein provisions are made for plugging the port when the burner is inoperative.

Many furnace installations are fired by a plurality of fuel burners, each of which communicates with the furnace combustion chamber through a port formed in one of the furnace chamber boundary walls. Because of limited turndown capabilities of an individual burner, it is common practice to vary the total firing rateto the chamber by taking one or more burners out of service. In many of these multi-burner installations, the air is supplied to a group of burners through a common plenum or windbox. Each burner normally includes an air register which communicates with the windbox and is arranged to direct air, usually in a circular path, into and through the burner air port in mixing relationship with the fuel discharged through the burner via a suitable fuel introduction element. Since the primary function of the air register is to direct and control the air flow stream to an individual burner during normal operation, it is ofttimes impossible to completely shut off the air flow to an individual burner, when it is not in'operation, by merely closing the register. Moreover, in many installations it is desirable that there be a significant amount of air leakage through the air register in order to provide sufilcient cooling to the burner parts which are exposed to radiation from within the furnace chamber.

Regarding the above-mentioned leakage through a closed burner register, it is quite common that this leakage be as much as 10-15% of the full load air flow through the burner. Thus, it is apparent that when one or more burners are out of service, the leakage through the idle burners is sufficient to upset the total excess air control of the furnace chamber, and thereby adversely affect operation of the furnace, particularly when the furnace is used to supply heating gases to a vapor generator. Furthermore, in certain chemical recovery furnaces, close control of total excess air to within specified limits is necessary to maintain a proper chemical balance and thus to foster-the desired chemical reactions. In these furnaces the normal leakage of air through idle burners would be totally intolerable because of its adverse effect on the chemical balance within the furnace chamber.

Accordingly, it is an object of the present invention to provide a fuel burner having associated therewith a plug which may be selectively positioned within the burner ing construction details 3,339,614 Patented Sept. 5, 1967 still further object of the present invention that this burner plug arrangement be such that the plug is housed wholly within the burner-windbox housing structure so as to avoid any necessity for redesigning the walls of the combustion chamber to accommodate the burner plug.

These objects are attained according to the present invention in a fuel burning apparatus for firing through a port in a wall of a combustion chamber. The burner includes a burner throat aligned with the port, and a burner housing enclosing a passage communicating with the port. The fuel burner is preferably enclosed within a combustion air windbox, and a vaned circular register is mounted adjacent the throat and circumscribing the burner passage for directing air into and through the port. A fuel introduction element is provided for introducing fuel in mixing relationship with the air flowing through the port. A burner plug, having the same general shape as the port, is disposed within the housing, which is formed with a laterally extending plug storage cavity. The burner plug is eccentrically mounted on an operating rod which extends outside the burner, and suitable mechanism is provided for rotating the rod to move the plug between a stored position within the cavity and a position in axial alignment with the burner throat and port. Provisions are also made for withdrawing the fuel introduction element to a position behind the storage cavity, and for axially moving the .plug along the burner passage and into engagement with the peripheral walls of the burner throat.

For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the following description which refers to the accompanying drawing in which FIG. 1 is a partially diagrammatic sectional side view of a fuel burning apparatus according to the present invention; FIG. 2 is an enlarged sectional view taken along line 22 of FIG. 1; and FIG. 3 is a sectional View showof the burner plug.

Referring to the drawings, FIGS. 1 and 2, a fuel burner assembly 10 is arranged to fire through a circular port 11 formed in a fluid cooled wall 12 of a furnace combustion space or chamber 13. Spaced from and parallel with the wall 12 is an insulated burner windbox front wall 14, the space between the walls 12 and 14 delimiting a plenum chamber or windbox 15 to which pressurized combustion air is supplied from a suitable source (not shown). The burner assembly 10 includes a generally cylindrical housing 20 which is attached at its outer end to a front cover plate 21, which is suitably connected, as by bolting, to the wall 14. The housing 20 encloses a generally cylindrical passage 22, which is circumscribed by a circular vaned register assembly 25 disposed within the windbox 15 and near the end of the passage 22 adjacent'the chamber wall 12. The register assembly 25 is of known construction and is provided with an operating shaft 27 extending through the front cover plate 21. A handle 28 is connected to the shaft and may be operated to selectively open and close the vanes of the register in a known manner. Disposed between the register assembly 25 and the wall 12 is a converging frusto-conical throat section 26 which terminates immediately adjacent the narrowest portion of the port 11. The opposite end of the housing 20 is suitably closed by an end closure 23.

A fuel introduction element 30 is mounted on and extends through the end closure 23 and is disposed coaxially with respect to the housing 20, register 25, throat portion 26 and port 11. The distal end of the fuel introduction element 30 is provided with a suitable impeller 31 of a known type. The opposite end of the fuel introduction element is suitably provided with fittings for connection with a supply of fluid fuel from a source (not shown). An impeller rod 32 connects with the impeller 31 and extends through the end closure 23 so that the impeller 31 can be properly ositioned during operation. The mounting of the fuel introduction element 30 through the end closure 23 is accomplished by means of a tubular sleeve 33 that is rigidly attached to the closure and through which the fuel element 30 is axially slidable. Guide roller 34, engaging the fuel element 30, is provided on the inner end of the sleeve 33 to facilitate axial movement of the fuel element 30.

Extending laterally from the housing 20 are walls 35 which enclose a relatively narrow burner plug storage cavity 36, the general outline of which is best shown in FIG. 2. A circular burner plug 40 is eccentrically attached to an operating rod 41 which extends through and is supported in a sleeve 42 rigidly attached to the end closure 23. Mounted on the outside of the end closure 23 is a plug operating mechanism 45 which is arranged to rotate the operating rod 41 and the attached plug 40, and to also permit axial movement of the rod 41. Suitably, the mechanism 45 may include a worm gear drive (not shown) to effect rotation of the rod 41. The rod 41 may, for example, be keyed to the mechanism 45 so as to perrnit extensive axial movement of the rod 41. A rollersupport 46 mounted on the inner wall of the housing 20 engages the rod 41 and serves to facilitate its axial movement.

Referring particularly to FIG. 3, the plug 40 includes a pair of spaced parallel circular plates 47 connected at their outer edges by a cylindrical plate 48 to define a cylindrical space which is filled with suitable refractory material 49. It should be recognized that the outer diameter of the cylindrical plate 48 is of slightly smaller diameter than the smallest diameter of the port 11. Attached to the cylindrical plate 48 and extending rearwardly therefrom is an outwardly projecting frusto-conical seal plate 50 that is arranged to mate and engage with the throat portion 26 when the plug is positioned within the port 11. Connected to one side of the plug 40 is a sleeve 51 which connects with the operating rod 41. A connecting pin 52 projects from the axis of the plug 40 and is arranged to engage with a suitable mating opening (not shown) formed in the distal end of the fuel element 30.

In the drawings, FIGS. 1 and 2, the plug 40 is shown as being disposed in its inoperative or stored position within the cavity 36. When it is desired to isolate the burner from the furnace chamber 13, the fuel supply to the fuel introduction element 30 is first shut off, and any necessary purging thereof is accomplished. The element 30 is then retracted (the retraction being facilitated by means of the roller assembly 34) to a position (shown in phantom at 31') behind the cavity 36. The burner plug 40 is then rotated, by means of mechanism 45, from its stored position into a position in axial alignment with the port 11. In this regard, it should be noted (see FIG. 2) that the walls 35 forming the cavity 36 are so arranged to accommodate the swinging of the plug 40 between the stored position and the position in axial alignment wtih the port 11. Having positioned the plug 40 axially with respect to the port 11, the fuel element 30 is moved forwardly into engagement with the plug 40 (using pin 52), and the plug is then urged into engagement with the throat portion 26 by forward movement of the fuel element 31 and/ or the operating rod 41. In FIG. 1, the plug 40 is shown in its port-closing position in phantom at 40. The plug 40, when in position in the port 11, is maintained in place due to the engagement of the fuel introduction element 30.

When desired to return the burner 10 to operation, the plug 40 may be retracted and thereafter axially rotated into the stored position in cavity 36 by means of appropriate manipulation of the mechanism 45 and the fuel element 30. The fuel element 30 may then be returned to its forward operating position, and firing may be commenced.

What is claimed is:

1. Fuel burning appartus for firing through a port in a wall of a combustion chamber comprising means defining a burner throat aligned with said port, a burner housing enclosing a passage communicating with said port, means for directing combustion air through said port including a register adjacent said throat and circumscribing said passage, a fuel introduction element mounted on said housing for introducing fuel in mixing relationship with the air flowing through said port, a burner plug disposed within said housing and engageable with said throat, said housing formed with walls enclosing a laterally extending plug storage cavity, and means for positioning said plug within said throat to close said port.

2. Fuel burning apparatus according to claim 1 wherein the means for directing air further includes a windbox wall on which said housing is mounted, said windbox wall being spaced from the wall of the combustion chamber to enclose therebetween an air plenum in which said register and said storage cavity are disposed.

3. Fuel burning apparatus according to claim 1 wherein said register is disposed between said cavity and said throat.

4. Fuel burning apparatus according to claim 1 wherein the means for positioning said plug includes an axially movable operating rod mounted on said housing and eccentrically connected with said plug, and means for rotating said rod to move said plug between a stored position within said cavity and a position in axial alignment with said throat.

5. Fuel burning apparatus according to claim 1 wherein said throat is formed with an inlet portion having a surface facing away from said port, and said plug includes an outwardly projecting peripheral seal ,plate arranged to mate with said surface.

6. Fuel burning apparatus according to claim 4 wherein said fuel introduction element is axially movable to a position more remote from said throat than said storage cavity, whereby said plug may be moved from said storage cavity to a position between said throat and said fuel introduction element.

7. Fuel burning apparatus according to claim 6 wherein means are provided for engaging said fuel introduction element and said plug.

'8. Fuel burning apparatus according to claim 2 wherein said positioning means includes an axially movble operating rod mounted on said housing and eccentrically connected with said plug, and means for rotating said rod to move said plug between a stored position within said cavity and a position in axial alignment with said throat.

9. Fuel burning apparatus according to claim 8' wherein said fuel introduction element is axially movable to a position more remote from said throat than said storage cavity, whereby said plug may be moved from said storage cavity to a position between said throat and said fuel introduction element.

References Cited UNITED STATES PATENTS 1,206,292 11/1916 Best 1584 1,391,338 9/1921 Morse 1S82 1,628,470 5/1927 Morse 1582 1,797,570 3/1931 Ferguson 158-11 FREDERICK L. MATTESON, IR., Primary Examiner.

E. G. FAVORS, Assistant Examiner. 

1. FUEL BURING APPARATUS FOR FIRING THROUGH A PORT IN A WALL OF A COMBUSTION CHAMBER COMPRISING MEANS DEFINING A BURNER THROAT ALIGNED WITH SAID PORT, A BURNER HOUSING ENCLOSING A PASSAGE COMMUNICATING WITH SAID PORT, MEANS FOR DIRECTING COMBUSTION AIR THROUGH SAID PORT INCLUDING A REGISTER ADJACENT SAID THROAT AND CIRCUMSCRIBING SAID PASSAGE, A FUEL INTRODUCTION ELEMENT MOUNTED ON SAID HOUSING FOR INTRODUCING FUEL IN MIXING RELATIONSHIP WITH THE AIR FLOWING THROUGH SAID PORT, A BURNER PLUG DISPOSED WITHIN SAID HOUSING AND ENGAGEABLE WITH SAID THROAT, SAID HOUSING FORMED WITH WALLS ENCLOSING A LATERALLY EXTENDING PLUG STORAGE CAVITY, AND MEANS FOR POSITIONING SAID PLUG WITHIN SAID THROAT TO CLOSE AND PORT. 